A white woman who accused Emmett Till of verbally and physically accosting her in Mississippi in 1955 – inflaming tensions around the murder that helped spark the civil-rights movement — has admitted she lied, according to a new book.

Till, who was 14 at the time of his brutal death, had allegedly whistled at Carolyn Bryant, a 21-year-old white woman, while at a country store in Money, Mississipppi. Bryant’s husband and a second white man later tracked Till down and shot and bludgeoned him to death — and were acquitted by an all-white, all-male jury after an hour’s deliberation.

During the trial, Bryant testified that Till had also made physical and verbal advances toward her, a sensational claim that worsened tensions over the case. But according to a 2007 interview newly revealed in the book “The Blood of Emmett Till,” Bryant admits that never happened.

“That part’s not true,” she told writer Timothy Tyson, according to Vanity Fair, though she claimed she could not recall what happened the rest of the evening at her husband’s country store, where Emmett stopped by briefly on Aug. 24, 1955, to buy 2 cents worth of gum.

The Chicago boy, who had been visiting relatives in the segregated cotton country of the Deep South, was kidnapped, beaten and shot four days later.

He had a bullet hole in the head, barbed wire around his neck, an eye gouged out and other ghastly wounds. His body was dumped in the muddy Tallahatchie River.

“Nothing that boy did could ever justify what happened to him,” she is quoted as saying.

Bryant, 82, is now known as Carolyn Bryant Donham. Her court testimony was out of the earshot of the jury, but helped to frame the case publicly.

She testified that Till had grabbed and threatened her inside the store – and that he had used an “unprintable” word when he told her he had been intimate “with white women before.”

“I was just scared to death,” she said in court.

The two killers later admitted their guilt after their acquittal.

Till’s murder became the flashpoint in the American civil-rights movement. His mother even insisted on an open-casket funeral, leading to photographs of his battered corpse being spread across the country, which helped focus public attention on what was happening in the heart of the country.

In 2004, the FBI reopened the case to see if any accomplices could be hauled to court, but a grand jury decided three years later that there was insufficient evidence to pursue charges.

Bryant went into hiding after the trial – divorcing and marrying twice more — and remained mum on the case until she gave the interview with Tyson.

She told him she “felt tender sorrow” for Emmett’s mother, Mamie Till-Mobley, who died in 2003, but he doesn’t mention if she expressed guilt or apologized.

Civil-rights pioneer Rosa Parks has said she thought about Emmett when she refused to give up her seat on a bus in Montgomery, Alabama, a few months after his death.

The shocking crime was memorialized in Nobel laureate Toni Morrison’s play “Dreaming Emmett,” a Langston Hughes poem and a song by Bob Dylan.

The whereabouts of the now-82-year-old Donham are unknown.

“That case went a long way toward ruining her life,” Tyson told Vanity Fair.